Question 19.3

comp.lang.c FAQ list · Question 19.3

Q: How can I display a percentage-done indication that updates itself in place, or show one of those ``twirling baton'' progress indicators?

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A: These simple things, at least, you can do fairly portably. Printing the character '\r' will usually give you a carriage return without a line feed, so that you can overwrite the current line. The character '\b' is a backspace, and will usually move the cursor one position to the left.
Using these characters, you can print a percentage-done indicator:

for(i = 0; i < lotsa; i++) {
  printf("\r%3d%%", (int)(100L * i / lotsa));
  fflush(stdout);
  do_timeconsuming_work();
 }
 printf("\ndone.\n");

or a baton:

printf("working: ");
 for(i = 0; i < lotsa; i++) {
  printf("%c\b", "|/-\\"[i%4]);
  fflush(stdout);
  do_timeconsuming_work();
 }
 printf("done.\n");

See also question 12.4.
References: ISO Sec. 5.2.2